A periodontal disease is a bacterial infection that is developed through an infection of periodontal tissue with oral bacterium.
The diagnosis of periodontal disease in a dental clinical site is carried out based on overall results of clinical tests such as a clinical condition, a photograph of oral cavity, a radiographic image or a periodontal tissue test. Among these tests, the photograph of oral cavity and the radiographic image exploration visually evaluate the morphological change of periodontal tissue, and periodontal tissue test evaluates by measuring various clinical items such as the state of the formation of plaque, the depth of a periodontal pocket, the presence of bleeding during probing or the degree of tooth mobility. Therefore, these tests require complicated operations and a practitioner must have advanced technique for accurately diagnosing the periodontal disease pathologic condition of patients.
In other words, in some cases, a test result may vary depending on the skill level of practitioners, and therefore different diagnoses may be given to a patient. Further, in the clinical dental tests as mentioned above, in spite of a fact that a periodontal disease is a bacterial infection, the periodontal disease is evaluated not at “a level of infection” with a periodontal disease-causing bacterium but at a level of “the morphological change” of periodontal tissue; in other words, the test is carried out by the practitioner's subjectivity. Therefore, there have been a demand for an objective periodontal disease test method which is reasonable from the bacteriological and immunological viewpoints and in which difference in a test result would not occur depending on the skill level of practitioners.
In these situations, a periodontal disease test system is carried out, in which a serum antibody titer against a periodontal disease-causing bacterium is employed as a measure for the periodontal disease testing (Chieko KUDO, Journal of Okayama Dental Society, vol. 28 (1) (2009), pp. 1-14). In this periodontal disease test system, the state of infection with a periodontal disease-causing bacterium or the severity of a periodontal disease (the state of inflammation) is evaluated by detecting/quantifying “a specific antibody” against the periodontal disease-causing bacterium from a trace amount of blood that is collected from a finger tip of a patient and then is separated. According to this system, it is possible to objectively and uniformly evaluate the disease condition of a periodontal disease by employing an immunological technique.
Further, in this periodontal disease test system, plasma is separated from the blood collected from a finger tip, a sample of the plasma is mailed to an inspection agency, an IgG antibody titer against a periodontal disease-causing bacterium is measured in the inspection agency, the severity of a periodontal disease is evaluated, and then a result of the periodontal disease test is notified to each patient (a test on a plasma antibody titer against a periodontal disease-causing bacterium). Thus, the periodontal disease test can be assisted in general practitioners or at home. Further, since test data are comprehensively collected and analyzed, it becomes possible to correlate the test data with disease conditions using an enormous quantity of data.
Meanwhile, in the periodontal disease test system mentioned above, since a large quantity of samples is handled, it is required to treat the samples automatically and at a high speed.
In the test system, the correlation between test results and a periodontal disease become higher with the increase in the types of antibodies against an antigen to be tested in a (blood) sample, and thus the periodontal disease can be tested with higher accuracy. In addition, in a human suffering from periodontal disease, the type of periodontal disease-causing bacterium antigen to be recognized is varied due to the inter-individual differences in the periodontal disease-causing bacteria and the human. Also in this regard, a periodontal disease can be tested with higher accuracy with the increase in the types of antibodies to be tested.
However, if the antibody titers of a variety of antibodies are to be measured, it is difficult to treat samples at a high speed, which is not suitable for automated test using a device.
The antigen used in the current antibody titer measurements is a solution prepared by disrupting a periodontal disease-causing bacterium such as Porphyromonas gingivalis, which is a mixture containing a wide variety of bacterial proteins (including LPSs and membrane lipids). Therefore, it has been difficult to treat a large quantity of samples automatically and at a high speed using a device.